Rhopalotria (Rhopalotria) dimidiata Chevrolat, 1878

O’Brien, Charles W. & Tang, William, 2015, Revision of the New World cycad weevils of the subtribe Allocorynina, with description of two new genera and three new subgenera (Coleoptera: Belidae: Oxycoryninae), Zootaxa 3970 (1), pp. 1-87 : 23-25

Rhopalotria (Rhopalotria) dimidiata Chevrolat, 1878

Figures: habitus: 21–24; antennal pockets: 106; male genitalia: 135–136, 178, 218; female genitalia: 245, 266.

Rhopalotria dimidiata Chevrolat, 1878 : XCVII

Illustrations and an extensive description based on Cuban specimens are given by Muñiz & Barrera (1969) in Spanish. The specimens on which it is based have been lost and cannot be verified and here we present a description based on specimens from the Cayman Islands.

REDESCRIPTION—Body minute to medium-sized (range 1.9–3.2 mm, mean = 2.7 mm, n = 63), robust, broad-oval; distinctly bicolored, orange and black.

Male. Rostrum: moderately long, 1.03 X longer than pronotum, brownish orange; moderately, coarsely, subrugosely punctate nearly to apex, there weakly expanded; moderately but evenly curved in lateral view. Head: with entire dorsum excluding median area of forehead, moderately coarsely, not rugosely punctate; forehead with short deep median groove, with margins of groove impunctate; median area between apical margins of eyes ca. 3/4 wider than between basal margins of eyes. Antennae: scape 0.70 X as long as eye and as long as desmomeres 1+2, 3–4 shorter but elongate, 5–6 rounded, 7 transverse; scape, funicle and club brownish orange with apical rhopalomere pale yellowish. Prothorax: strongly transverse, 1.43 X wider than long; apex moderately narrow, evenly expanded to slightly narrowed rounded base; lateral margins with minute denticles; disc with moderately coarse, dense, not contiguous punctures, laterally subrugose; individuals with pronotum, dorsal surface of head and profemora with fine reticulation visible under high magnification 40–100X; uniform brownish orange. Scutellum: moderately subquadrate, apex rounded, with sparse coarse punctures. Elytra: 1.54 X longer than wide; subparallel behind rounded humeri, to scarcely expanded near declivity, there suddenly evenly narrowed to broadly rounded moderately emarginate apices; unevenly coarsely punctate, humeral area with discrete punctures, medially and apically angulately rugosely punctate; entire basal 2/5 brownish orange, remainder black. Legs: very robust, procoxae protruding, with single subacute inner apical process; profemora very strongly asymmetrically swollen, with apical pit-like impression, receiving base of tibia, each margin with small apical tooth; protibiae very stout in lateral view, with base very strongly rounded with right angle bend, moderately large tooth on anterior inner surface near base, inner surface moderately submedially narrowly excavate from base to near apex, apex with large curved anterior mucro, and smaller apically directed tooth. Length, pronotum and elytron: 2.60 mm.

Female. Same as male except: Rostrum: long, 1.36 X longer than pronotum, very weakly expanded apically. Prothorax: 1.53 X wider than long; sides more or less evenly rounded from narrow apex to slightly narrowed base. Elytra: 1.44 X longer than wide. Legs: with protibiae lacking inner basal tooth, inner surface with moderately shallow excavation, two apical teeth small and subequal in size. Length, pronotum and elytron: 3.00 mm.

Genitalia and Associated Structures— Male. Length of penis and apodemes together 0.69–0.72 mm (n = 3). Penis: in dorsal view subparallel to slightly tapering distad, tapering increasing sharply at gonopore, with angle between sides ~ 45˚ (Andros Is.) to ~ 90˚ (Cayman Is.) to subtruncate apex (Figs. 135, 178). Tegmen: apical visor short <1/8 own width; distal margin with 9 setae (Cayman Is.) to 12 setae (Andros Is.) (Fig. 218). Female. Sternite VIII: 0.65–0.75 mm long (n = 3), arms slightly shorter than apodeme, diverging from apodeme with slight angle (<20˚) between arms for ~ 3/10 of length, then diverging at moderate angle (~ 45˚) for another ~ 3/10 of length, then bending inward and becoming subparallel, to slightly convergent near apices (based on specimens from Andros Island, Bahamas) (Fig. 245).

Intraspecific Variation— Morphological comparison of specimens from the Bahamas, including Abaco, Andros, Eleuthera, Grand Bahama, Long Island and New Providence Islands, with those from the Cayman Islands suggests small differences in male RL/PL (Bahamian populations: range = 1.06–1.24, mean = 1.16, n = 20; Cayman population: range = 1.16–1.30, mean = 1.22, n = 12) and PW/PL (Bahamian populations: range = 1.38– 1.54, mean = 1.45, n = 20; Cayman population: range = 1.48–1.65, mean = 1.54, n = 12). Molecular analysis of the 16S rRNA mitochondrial gene in Bahamian populations indicates that they are genetically identical in this gene sequence ( Tang et al. in prep.). Rhopalotria from the Cayman Islands display a slight difference in this gene with those from the Bahamas. No genetic data are available for specimens from Cuba, which is situated geographically between these two other land masses. Until more genetic or morphological evidence becomes available we treat the Cuban, Cayman Islands and Bahamian populations as one species. Surveys in Hispaniola and Puerto Rico indicate that Rhopalotria is absent from these islands ( Tang & O’Brien, 2012).

Remarks— Morphologically R. dimidiata is very similar to R. slossoni specimens from Florida and is distinguished by its black elytra with brown spanning the entire basal region and the lower degree of fusion in the sensory pockets of rhopalomeres 1 and 2 of the club (Figs. 106–107). Molecular analysis of the 16S rRNA mitochondrial gene from R. dimidiata populations in the Bahamas and the Cayman Islands indicates differences in the sequence of this gene compared with R. slossoni in Florida ( Tang et al. in prep.).

Biology— This species develops and reproduces in the male cones of many forms of the Zamia pumila complex on the various islands of its range.

Type Locality— “Ins. Cuba ” .

Range— Known from Cuba, Isle of Youth [= Isle of Pines], the Cayman Islands, and in the Bahamas on Abaco, Andros, Eleuthera, Grand Bahama , New Providence and Long Island.

Material Examined— BAHAMAS: Abaco: Tilloo Cay Reserve, coastal scrubland, [GPS coord. omitted], ex ♂ cone Zamia sp. , 8-II-2011, M.Calonje, S.Gilmer et al. (32); Abaco Nat. Park, pineland, [GPS coord. omitted], ex Zamia sp. ♂ cone, 9-II-2011, M.Calonje & J.Francisco-Ortega (6); Andros: 3km N. of San Andros, pine forest, [GPS coord. omitted], 10m, ex ♂ cone Zamia sp. , II-21-2010, M. Calonje & A. Meerow (28); Twin Lakes, coppice in pine forest, [GPS coord. omitted], 10m, ex ♂ cone Zamia sp. , II-23-2010, M. Calonje & A. Meerow (13); Eleuthera: So. Palmetto Point, limestone bluff W. of docks, 10m, [GPS coord. omitted], III-1-2010, M. Calonje, R. Adams et al. (2); Gaulding Cay Beach, dunes & thickets, [GPS coord. omitted], ex ♂ cone Zamia angustifolia , 11-II-2011, M.Calonje & L.Johnson (44); S. of Ten Bay Beach, limestone hills, [GPS coord. omitted], ex ♂ cone Zamia sp. , 12-II-2011, M. Calonje & L. Johnson (32); Grand Bahama: Freeport, E.of Fishing Hole Rd, [GPS coord. omitted], ex ♂ cone Zamia sp. , 4-II-2011, M. Calonje & J. Francisco-Ortega (17); Long Island: Pettys, E coast sand dune, [GPS coord. omitted], ex ♂ cone Zamia lucayana , I-28-2012, W. & L. Tang (179); Buckleys, E coast sand dune, [GPS coord. omitted], 18m, ex ♂ cone Zamia lucayana , I-29-2012, W. & L. Tang (139); New Providence: 0.5km S. Lynden Pindling airp., pine forest, 6m, [GPS coord. omitted], III-7-2010, M. Calonje & J. Francisco-Ortega (37). CAYMAN ISLANDS: Cayman Brac: W. I., The Creek, 5–9-IV-97, E.A. Dilbert, Blacklight Trap (3); Maj. Donald Dr. (sw), ♂ cone Zamia sp. , emerge 20–22-I-2013, W. Tang (47); Maj.Donald Dr., farm [GPS coord. omitted], Zamia sp. ♂ cone, coll 20-I, emerge 23–31-I-2013, W. Tang (30); Songbird Dr., ♂ cone Zamia sp. , emerge 19–21-I-2013, W. Tang (22); Grand Cayman: Salina Reserve , north area 29 Dec. 1992, F. J. Burton, ex. single male cone (in anthesis) Zamia pumila L. (cycad) (16). CUBA: Bowing 63–47* Derelomus? Dimidiatus Ch Cuba/Dimidiatus Cuba (Derel.?) (Ch.)/ New Gen. (1); Isle of Pines [Isle of Youth]: nr. Rio Callejon, nr. Santa Barbara, I:3–7:1950, L. Ross, Reared from Cycas [ Zamia ] (4); Matanzas: Varadera, 10-I-62, A. Barrera s/ Zamia [lost from point in UNAM collection.] (0). Holotype not seen. Specimens (652) are deposited at ANIC, ASUT, BMNH, CAS, CMNC, CSCA, CWOB, EMEC, FMNH, FSCA, IADIZA, IEXA, INbio, IZCAS, MIUP, NMHN, STRI, UCFC, UNAM, USNM, ZMHB.